Audio Specification

Similar to our upload specifications for video, we'll always do our best to handle what you bring to our platform, but we do have recommendations to make your experience as seamless as possible.

A full list of supported audio formats can be found here. 

Audio Requirements

Here's a breakdown of all the details you'd need to know for how we handle the sound in your videos:

  • AAC-LLC or PCM - Files will maintain original 5.1 or Atmos channels when exported from Flow Capture as we utilize a non-destructive import.
  • EAC3 / Surround Sound - This will be copied directly to the transcoded streams for playback. Multichannel 5.1 and 7.1 muxed streams will be transcoded into the output to create a stereo conversion for non-surround playback.

Working with Audio on Flow Capture

Once a file is uploaded to our platform, our system will detect and process the audio tracks on it according to the following methods.

No Audio

A silent stereo channel is added during processing

Stereo

The channel labelled as Stereo is what will be used for playback unless you're using multichannel audio

  • If there is a single muxed stereo stream labeled with a stereo layout then it will be selected and transcoded into the output     
  • If there is a single muxed stereo stream it will be transcoded into the output     
  • If there is a single stream it will be transcoded into the output

5.1 Multi-Channel

If you're looking to go beyond stereo, Flow Capture supports the following multi-channel audio formats, all of which can be found in a folder's Upload Settings. We default to automatically detecting the type of layout in all uploaded files and handling them using the methods outlined above, with SMPTE ordering as our default.

  • 5.1.2 (SMTPE ordered)
  • 5.1 (SMTPE ordered)
  • 5.1.2 (Film ordered)
  • 5.1 (Film ordered)
  • Dual Mono

Generally speaking, you can leave the Multi-Channel Audio Layout option set to Auto, the default. You'll only need to specify this option if the file that you're uploading has enough audio tracks that it could be mistaken for another type of ordering, or if you need to specify Film over the default SMPTE ordering. 

We also support some Dolby-specific formats:

  • EAC3, for Dolby Digital 5.1
  • EAC3-JOC, for Dolby Atmos

With those, we'll port the audio track of either EAC3 format directly into the video files that we generate for playback. Our SMPTE ordered downmix is as follows:

You don't need to specify or label the channels in your file - we default to reading them in the standard SMPTE formats. 

7.1 Multi Channel and Dolby Atmos

We support the following formats for Dolby Digital Plus with Dolby Atmos content audio streams, including an interleaved .wav with channel-based immersive content:

  • A 16-track interleaved in a 9.1.6 channel configuration (L, R, C, LFE, Ls, Rs, Lrs, Rrs, Lw, Rw, Lfh, Rfh, Ltm, Rtm, Lrh, Rrh)
  • A 12-track interleaved in a 7.1.4 channel configuration (L, R, C, LFE, Ls, Rs, Lrs, Rrs, Lfh, Rfh, Lrh, Rrh)
  • A 10-track interleaved in a 5.1.4 channel configuration (L, R, C, LFE, Ls, Rs, Lfh, Rfh, Lrh, Rrh)
These channels should be included either as discrete PCM channels within the MOV file or muxed in the order listed above.

Channel Glossary

Here's a breakdown of each channel and its accompanying abbreviation:

  • Left (L)
  • Right (R)
  • Center (C)
  • Low Frequency (LFE)
  • Left Side Surround (Ls or Lss)
  • Right Side Surround (Rs or Rss)
  • Left Rear Surround (Lrs)
  • Right Rear Surround (Rrs)
  • Left Width (Lw)
  • Right Width (Rw)
  • Left Top Front (Ltf)
  • Right Top Front (Rtf)
  • Left Top Middle (Ltm)
  • Right Top Middle (Rtm)
  • Left Top Rear (Rtm)
  • Right Top Rear (Rtr)

Audio Playback

Files that have been uploaded to Flow Capture are encoded for playback along the following guidelines. They otherwise maintain quality specifications that have been provided.

  • Mono/Stereo/Multi-Channel - AAC codec at 96kbps-112kbps per audio channel
  • Atmos - This will be the same EAC3-JOC file that was uploaded with the source video.

Note that support for 5.1 output is currently limited to the following scenarios:

  • An Apple TV using the Flow Capture App connected to a 5.1 or Atmos-capable sound bar
  • Safari or Microsoft Edge connected via HDMI to a 5.1 or Atmos-capable sound bar

Here's a list of Apple devices that support Spatial Audio. More information on Spatial Audio can be found in Apple's documentation.